- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- computer statistical experiment
- statistical optimization
- resonant-tunneling diode
- negative voltage current differential resistance
- characteristics
- heterojunction
- quantum well
- resonant tunneling border
- Electronic Science and Technology
- Optoelectronic Information Science and Engineering
- Bauman Moscow State Technical University
- V.N. Karazin Kharkiv National University
-
Surface-modification of Cu2O nanoparticles towards band-optimized hole-injection layers in CsPbBr3 perovskite light-emitting diodes
摘要： Herein, we have proposed a strategy to grow surface-modified cuprous oxide (Cu2O) nanoparticles as an efficient hole-injecting layer (HIL) in all-inorganic cesium lead bromide (CsPbBr3) perovskite light-emitting diodes (PeLEDs). Surface of the oxide nanoparticles was modified by different ligands (thiols or silane) which in turn tailored its conduction and valence band-edge energies. As evidenced from the density of states (DOS) spectra, such modification of band-edge energies tuned the band-alignment at the perovskite-HIL interface influencing the efficiency of the PeLEDs thereby. The device performance has been correlated with the band-diagram of the heterojunctions. The report hence provides a strategy to achieve a favorable band-alignment in perovskite-based heterojunctions for optoelectronic applications.
关键词： scanning tunneling spectroscopy,Cu2O nanoparticles,band-engineering,surface-modification,perovskite light-emitting diodes.
更新于2025-09-11 14:15:04
-
Formation of Highly Ordered Terminal Alkyne Self-Assembled Monolayers on the Au{111} Surface through Substitution of 1-Decaboranethiolate
摘要： The reaction aimed at completing and closing the open cages of 1-decaboranethiol self-assembled monolayers (SAMs) on Au{111} with 4-phenyl-1-butyne results in highly ordered monolayers of 4-phenyl-1-butyne. The initially disordered 1-decaboranethiolate changed into ordered (√3×√3)R 30° lattices on Au{111} typical of alkyne SAMs, indicating the complete substitution of 1-decaboranethiolate moieties, as determined by nanoscale imaging with scanning tunneling microscopy and X-ray photoelectron spectroscopy. Vibrational spectroscopy results indicate that the process happens gradually and that alkynyl groups are not totally oxidized in the ordered 4-phenyl-1-butyne monolayer.
关键词： Au{111},self-assembled monolayers,vibrational spectroscopy,scanning tunneling microscopy,X-ray photoelectron spectroscopy,4-phenyl-1-butyne,1-decaboranethiol
更新于2025-09-11 14:15:04
-
Embedded quantum dots in semiconductor nanostructures
摘要： In this work, we report the behavior of the tunneling current in a semiconductor nanostructure of (Ga, Al)As/GaAs which takes into account the behavior of the electrons and the Rashba’s spin orbit interaction in the presence of embedded quantum dots of di?erent geometries (lens, pyramid and ring) in voltage function, magnetic ?eld, and the di?erent values of the interaction spin orbit (π/2, π/4 and 3π/4). The results that were obtained show, that the intensity of the current presents appreciable changes when is changed the con?guration of the quantum dot as the intensities of external ?elds and spin polarization as well. All these internal and external e?ects that are studied in our model, signi?cantly modify the transport of information of the semiconductor nanostructure, our results show that the spin e?ects and the quantum dot con?guration contribute to the quantum memories e?ciency and the spin ?lter devices of actual use on nanoscience and nanotechnology.
关键词： quantum dots,Rashba’s spin orbit interaction,tunneling current,semiconductor nanostructures
更新于2025-09-11 14:15:04
-
Isotropic charge screening of anisotropic black phosphorus revealed by potassium adatoms
摘要： Black phosphorus has attracted great research interest due to its numerous applications in electronic devices, optoelectronic devices, energy storage, and so on. Compared with the majority of two-dimensional materials, black phosphorus possesses a unique property—its strong in-plane anisotropy. All the properties reported so far, including its effective mass, electron mobility, light absorption, thermal conductivity, and so on, have shown great anisotropy in the basal plane. This property renders black phosphorus applications not achievable with other two-dimensional materials. In this work, however, we discover a remarkable isotropic behavior in the strongly anisotropic black phosphorus—its electrostatic screening of point charges. We use the tip-induced band bending of a scanning tunneling microscope to map out the Coulomb ?eld of ionized potassium adatoms on black phosphorus and reveal its isotropic charge screening. This discovery is important for understanding electron scattering and transport in black phosphorus.
关键词： electron scattering,black phosphorus,isotropic charge screening,potassium adatoms,scanning tunneling microscope
更新于2025-09-11 14:15:04
-
Low-Noise Mid-Infrared Photodetection in BP/h-BN/Graphene van der Waals Heterojunctions
摘要： We present a low-noise photodetector based on van der Waals stacked black phosphorus (BP)/boron nitride (h-BN)/graphene tunneling junctions. h-BN acts as a tunneling barrier that significantly blocks dark current fluctuations induced by shallow trap centers in BP. The device provides a high photodetection performance at mid-infrared (mid-IR) wavelengths. While it was found that the photoresponsivity is similar to that in a BP photo-transistor, the noise equivalent power and thus the specific detectivity are nearly two orders of magnitude better. These exemplify an attractive platform for practical applications of long wavelength photodetection, as well as provide a new strategy for controlling flicker noise.
关键词： tunneling,low noise,heterojunction,mid-infrared
更新于2025-09-11 14:15:04
-
Influence of the Cation on the Surface Electronic Band Structure and Magnetic Properties of Mn:ZnS and Mn:CdS Quantum Dot Thin Films
摘要： The effects of doping Mn into ZnS and CdS quantum dots are reported. Scanning tunneling spectroscopy spectra show a reduction in the electronic band gap in both CdS and ZnS upon incorporation of the Mn dopant. Mn:ZnS exhibits a rigid band shift toward higher bias which is reminiscent of a hole doping effect. This rigid band shift in Mn:ZnS is argued, with the help of X-ray photoelectron spectroscopy, to be due to a hole-doping mechanism caused by the favorable formation of Zn vacancies and a reduction in S vacancies compared to undoped ZnS films. In CdS no rigid band shift is observed even though the presence of Cd vacancies can be confirmed by photoemission and magnetic measurements. A strong sp-d hybridization is observed in the Mn:CdS film upon introducing the Mn dopant. d0 ferromagnetism is observed in both undoped ZnS and CdS quantum dot thin films at room temperature. Upon doping of Mn into ZnS the magnetization is reduced suggesting an antiparallel alignment of Mn-Mn or Mn-Zn vacancies nearest neighbors. Density Functional Theory supports the experimental results indicating the nearest neighbor Mn atoms prefer antiparallel alignment of their magnetic moments with preferred ground state of Mn in 3+ oxidation state.
关键词： CdS,Mn doping,quantum dots,magnetic properties,scanning tunneling spectroscopy,electronic band structure,X-ray photoelectron spectroscopy,density functional theory,ZnS
更新于2025-09-11 14:15:04
-
Optimization of Transparent Passivating Contact for Crystalline Silicon Solar Cells
摘要： A highly transparent front contact layer system for crystalline silicon (c-Si) solar cells is investigated and optimized. This contact system consists of a wet-chemically grown silicon tunnel oxide, a hydrogenated microcrystalline silicon carbide [SiO2/μc-SiC:H(n)] prepared by hot-wire chemical vapor deposition (HWCVD), and a sputter-deposited indium doped tin oxide. Because of the exclusive use of very high bandgap materials, this system is more transparent for the solar light than state of the art amorphous (a-Si:H) or polycrystalline silicon contacts. By investigating the electrical conductivity of the μc-SiC:H(n) and the influence of the hot-wire filament temperature on the contact properties, we find that the electrical conductivity of μc-SiC:H(n) can be increased by 12 orders of magnitude to a maximum of 0.9 S/cm due to an increased doping density and crystallite size. This optimization of the electrical conductivity leads to a strong decrease in contact resistivity. Applying this SiO2/μc-SiC:H(n) transparent passivating front side contact to crystalline solar cells with an a-Si:H/c-Si heterojunction back contact we achieve a maximum power conversion efficiency of 21.6% and a short-circuit current density of 39.6 mA/cm2. All devices show superior quantum efficiency in the short wavelength region compared to the reference cells with a-Si:H/c-Si heterojunction front contacts. Furthermore, these transparent passivating contacts operate without any post processing treatments, e.g., forming gas annealing or high-temperature recrystallization.
关键词： solar cell,tunneling,silicon,silicon carbide,transparent passivating contact (TPC),selective contact,photovoltaic cells,Passivating contact
更新于2025-09-11 14:15:04
-
Detailed Analysis and Understanding of the Transport Mechanism of Poly-Si-Based Carrier Selective Junctions
摘要： We investigate the transport mechanism of poly-Si-based carrier-selective junctions using the two-dimensional numerical semiconductor device simulations. The detailed transport model considers the charge carrier transport through the pinholes as well as tunneling through a very thin silicon oxide simultaneously. For the verification of the simulation model, the complete temperature dependent transfer length method is modeled and its results are verified with measurements of two different samples. By means of rigorous simulations, the influence of different pinhole geometrical and material parameters on junction resistivity are investigated and explained in detail. From the presented results, the fundamental understanding needed for optimizing the poly-Si-based carrier selective junction in respect to the main design parameters such as doping level in poly-Si, annealing time, silicon oxide thickness, and pinhole density is given. The detailed analysis shows the pinhole channel plays the most crucial role in the design of poly-Si-based carrier-selective junctions if the silicon oxide layer thickness is larger than 2 nm.
关键词： numerical simulations,tunneling,polysilicon on oxide,pinholes,Carrier-selective junctions
更新于2025-09-11 14:15:04
-
Electric-Field-Controllable Conductance Switching of an Overcrowded Ethylene Self-Assembled Monolayer
摘要： Molecular isomerism has been discussed from the viewpoint of tiniest switch and memory elements in electronics. Here, we report an overcrowded ethylene-based molecular conductance switch, which fulfills all the essential requirements for implementation onto electronic devices, namely, electric-field-controllable reversible conductance change with a molecular-level spatial resolution, robust conformational bistability under ambient conditions, and ordered monolayer formation on electrode surfaces. The conformational state of this overcrowded ethylene, represented by a folded or twisted conformer, is susceptible to external environments. Nanoscopic measurements using scanning tunneling microscopy techniques, together with theoretical simulations, revealed the electronic properties of each conformer adsorbed on Au(111). While the twisted conformer prevails in the molecularly dispersed state, upon self-assembly into a monolayer, a two-dimensional network structure of the folded conformer is preferentially formed due to particular intermolecular interaction. In the monolayer state, folded-to-twisted and its reverse isomerization can be controlled by the modulation of electric fields.
关键词： overcrowded ethylene,molecular conductance switch,scanning tunneling microscopy,electric-field control,self-assembled monolayer
更新于2025-09-11 14:15:04
-
Long wavelength type II InAs/GaSb superlattice photodetector using resonant tunneling diode structure
摘要： We report on a long wavelength type-II InAs/GaSb superlattice photodetector using resonant tunneling diode (RTD) structure. The linewidth of the satellite peak of the x-ray diffraction curve of the as-grown sample is only 15.7 arcsec showing a very high structural quality. The response maximum wavelength of the RTD detector is 7.5 μm and the 50% cutoff wavelength is 9.6 μm at 77 K. The measured QE is 147% at 7.5 μm when the applied bias voltage is 1.45 V and the corresponding responsivity is 8.9 A/W. This unusual QE is attributed to a large gain achieved when the device is under a resonant tunneling condition. The corresponding shot noise limited detectivity D* is 1.2×1010cm · Hz/W at 1.45 V at 77 K.
关键词： long wavelength,InAs/GaSb superlattice,quantum efficiency,resonant tunneling diode,type II
更新于2025-09-11 14:15:04